STATUS OF R&D AT UCSB Paul Szypryt Mazin Lab August 26, 2013
STATUS AS OF PALOMAR 2012
SCI-4
ARCONS Operated at 110 mK 8 ROACH boards for readout 350–1100 nm bandwidth, after filters 20x20 arcsecond field of view
Science Results Crab PulsarSDSS J % enhancement in optical flux coincident with Crab Giant Radio Pulses (GRPs)
CURRENT WORK
X-ray MKIDs KID inductor on SiN Membrane, capacitor on bulk Si Thermal Kinetic Inductance Detectors (TKIDs) X-ray hits absorber on island, heats island, breaks quasiparticles changes surface impedance
X-ray MKIDs Pulse lifetime of up to 1.6 ms Saturated, but noise and pulse shape imply <10 eV at 6 keV
Optical Membrane Devices
Membrane legs successful, even with 1x125 μm dimensions Some defects, but fairly high yield Tapered membrane edge and extra step plug to alleviate step coverage problems
Trenched Devices Trenching in Si near capacitor legs TiN capacitor remains on hills Reduce TLS noise
Trenched Devices
Carbon Nanotube Absorbers Currently growing CNTs on MKIDs to act as photon absorbers – potential for near 100% QE over a huge band! Ni catalyst added to inductor Plasma enhanced chemical vapor deposition using C2H2 and NH3 gas Can be used with TKIDs, where inductor is separate from absorber
Carbon Nanotube Absorbers Vertically aligned CNT forests are the only material that currently emulates a blackbody across the range of MKID sensitivity (~ μm). Can be placed near MKID inductors without increasing TLS noise Can currently grow CNTs on MKIDs, still need to refine photon detection process
Focused Ion Beam Milling Resonant frequency dependent on capacitance and inductance Very sensitive to inductor shape, less sensitive to capacitor shape Can remove capacitor material to reduce capacitance, and therefore increase resonant frequency
Focused Ion Beam Milling
Connection to ground at center of inductor, where fields should be smallest. May help with issues caused by floating pixels. Refined process to take advantage of NIST multilayer TiN, which is destroyed by HF etch in our current process. SCI-5 Array
JPL TiN filmNIST Multilayer TiN film
1.Deposit TiN Outline 2.Nb Feedline/Ground Plane 3.Dielectric for Crossovers 4.Nb Feedline Center strip 5.Gold Bond Pads 6.Pattern TiN SCI-5 Array
FUTURE PROJECTS
Palomar 2013 Improve quantum efficiency Microlens alignment stage Improving filtering Realuminizing Coudé flat Improve energy resolution Low-noise HEMT amplifiers ROACH-2 Eliminate hot pixels Virtual ground strap
ROACH-2 More FPGA resources Faster clock rates Better digital filters Increase pixels per ROACH board
Other Projects DARKNESS DARK-speckle Near-IR Energy-resolved Superconducting Spectrophotometer KRAKENS Keck Radiometer Array using KID Energy Sensors 180x180 pixels, 54x54” field of view, R = 20, Cassegrain focus Mega-z
Summary Palomar 2012 successful, but much room to improve Recent efforts: X-ray MKIDs Trenched Devices Carbon Nanotube Absorbers Focused Ion Beam Milling SCI-5 Array Design Aiming to improve QE, energy resolution, and yield, and to eliminate hot pixels, for next run